The present invention relates to conveyor belt cleaners which are used to remove residual material which clings to a conveyor belt. The removal of this residual material from the belt is especially troublesome where the material that adheres to the belt is very sticky or freezes to the belt. Such adherent materials are encountered, for example, with raw sugar belts, molasses belts, belts handling asphalt, belts conveying tar sands, belts conveying frozen foods and belts exposed to winter weather conditions.
A heated conveyor belt cleaner has been found to be useful in the removal of adherent material from a conveyor belt. In the use of heated belt cleaners, the ability to maintain a uniform scraper blade temperature is very important as is the ability to adjust the scraper blade temperature to different temperatures for particular uses. To prevent damage to the conveyor belt, the tip of the scraper blade must never reach a temperature that can break down the properties of the conveyor belt or melt into the conveyor belt. Most belts that are rubber coated and which are designed for elevated temperatures have an upper temperature range of approximately 450.degree. F. which can easily be exceeded by many common heating means. In contrast, belts which are exposed to extreme weather conditions are usually designed for low temperature flexibility, and not elevated temperatures, requiring the scraper element temperature to be high enough to de-ice the belt, but not reach a high enough temperature to damage the belt surface.
The materials which are transported on a conveyor belt are often temperature sensitive requiring the scraper element temperature to fall within a certain range of temperatures. For example, if you are cleaning asphalt residue from the belt, the temperature range between having flowing liquid asphalt and cooking the asphalt into a solid coke-like material is fairly narrow. Mechanisms used for the removal of adherent materials are shown in U.S. Pat. Nos. 337,318, 867,739, 1,793,246, 2,878,926, 3,795,308 and 3,815,728. U.S. Pat. No. 4,182,444 discloses a mechanism for the heating of a scraper blade for the removal of adherent material.